Copper-zinc alloys



' be rolled hot.

Patented May 2, 1939 PATENT OFFICE COPPER-ZINC ALLOYS Wolf JohannesMiiller and Moritz Niessner, Vienna, Austria, assignors toOesterreichische Dynamit Nobel Aktiengesellschaft, Vienna, Austria, a.firm of Austria No Drawing. Application June 29, 1935, Serial No.29,102. In Austria July 21, 1934 3 Claims.

It is known that gamma-brass, that is to say copper zinc alloys'with acopper 'content of about 31-40%,1. e. alloys which are characterised bya low copper content, are more resistant to corrosion than the brassalloys of the alpha and alpha and beta region with for instance 68-72%and more of copper, i. e. ahigher'copper content. The technicalemployment of gamma-alloys poor in copper is however impossible, sincethese alloys are extremely hard and brittle and are consequently notmachinable.

From such alloys as is described in our prior Patent Nos. 2,006,598 and2,006,599, it has been disclosed that it is possible, by the addition ofa few percent of a metal soluble in gamma-brass or alloyable therewith,such as nickel or, with more advantage cobalt, preferably by asimultaneous addition of nickel and cobalt, to obtain alloys, whichpossess the good resistance to corrosion of gamma-alloys poor in copper,but are also capable of being worked up, that is to say can be treatedwith machine tools and can also Such alloys with an addition ofapproximately 340% of cobalt, nickel or the like individually or inmixture, that is to say for instance pure copper-zinc alloys with aminimum content of nickel of approximately 7-8% or of cobalt ofapproximately 5-6% have extremely good technical properties, and whencobalt and nickel are used simultaneously it is possible with a muchsmaller cobalt content to obtain the same effects as with the use ofcobalt alone. Consequently alloys that are deficient in copper, eventhose most deficient, can be made utilisable for industrial purposes oras constructional material for the production of articles, if thecopper-zinc alloys are alloyed with cobalt, nickel or the likeindividually or in mixture.

The present invention is based on the discovery that such copper-zincalloys containing cobalt,

nickel or the like, which contain copper in such an amount that theyhave a homogeneous mixed crystal or solid solution structure-that is tosay in a binary system copper-zinc alloyswith approximately 31-40%copper--, can be substantially improved in their properties by theaddition of other metals, i. e. metals which are soluble in the solidsolution of the alloy and are added or alloyed in an amount that is notgreater than corresponds to their solubility in the solid solution. Ithas been found that such alloys can be made capable of being moulded inthe cold state, i. e. rolled, pressed and drawn in the cold state by theaddition of such metals in amounts which are soluble in the solidsolutions so that the solid solution formation is maintained and theoccurrence of a heterogeneous structure is avoided. Such metals are forinstance aluminium, tungsten, tin, chromium, selenium, tellurium,titanl-- um, silver, silicon, iron, manganese, lead, molybdenum,zirconium etc. individually or two or more such metals combined asdesired, and of thesemetals, the best effect is obtained 'by those whichcause-an increase in fineness of the grain, that is to say moreespecially manganese, iron, lead,

silver. Phosphorus also produces this effect. By

such additions the region of the solid solution can also be somewhatextended with respect to that of the binary alloy, and alloyswithasomewhat higher copper content for instance with 45% copper content,which come in the beta and gamma region in the binary alloy, can be madesuitable for purposes for which they would otherwise be impossible owingto their copper content, such as for instance for cold rolling or for adrawing process.

In particular suitable are alloys with a copper content of at least 35%;such alloys, as compared with alloys with less copper content, have theadvantage of better workability.

By addition of such metals the alloy can be I improved in colour, moreespecially made whiter, and also favourably influenced as regards otherproperties, more especially made tougher, thus improving the capacityforbeing machined.

It is easily possible by empiric means to determine for each metal theamount which produces the most favourable effects.

It is more especially advisable to use the metals of the irongroup,'more particularly manganese. 46

- be assumed as more than 4% manganese.

which as compared with other metals, for instance as compared withaluminium, has the efiect that with an increasing content, i. e. up toabout 10%, there is an approximately proportional improvement in thecapacity of working up cold, whereas for instance aluminium in amountsof about 0.3% has an extremely favourable action, but in amounts of morethan 1. shows a diminished efiect.

The more deficient the alloy is in copper, the greater addition ofmanganese is necessary, and the lower limit for alloys deficient incopper must The higher the content of manganese, the better is thecapacity for being worked up cold, and one can go up to an addition ofabout 15% manganese. Suitable is an alloy which beside manganese,contains iron up to the limit-of solubility. which, depending on thecomposition of the alloy', may be 1 to 1.5%.

The addition of manganese has also the effect however that the additionof cobalt and nickel or the like can be reduced.

It is advisable to add very small amounts of phosphorus to such alloys,whereby a very considerable increase in the fineness of the grain oi thealloys can be obtained.

The cobalt or nickel content or content of cobalt and nickel in suchalloys according to the invention may be between about 3-12%.

Examples Suitable alloys according to the invention with manganese asadded metal have for instance the following composition, it beingclearly specified manganese content is smaller in the alloys ofrelatively high copper content than in the alloys of relatively lowcopper content.

however that the invention is naturally not limited to these examples:

Percent by weight What we claim is: 1. A corrosion resistant copper-zincalloy,

which is workable in the cold state, containing copper in an amount of30 to 45%, at least one metal of the group cobalt and nickel in anamount of 3 to 12% and in addition thereto manganese in an amount 4 to15%, the zinc, constituting substantially the the remainder.

2. An alloy according to claim 1 wherein the 3. An alloy according toclaim 1 -containing less than copper.-

WOLF JOHANNES Mt'irLLER. 35

MORITZ N'IESSNER.

